# AutoTypeTable

> A props table generated from a component's parameters, defaults and XML doc comments.

Source: https://shelldocs.shellui.dev/docs/components/auto-type-table

`AutoTypeTable` builds a props table for a registered component by reflecting on it. You name the component; the table lists every `[Parameter]` with its type, default and description. It replaces copying each prop into a `TypeRow` by hand, and it can't drift from the code.

## Basic use

```markdown
<AutoTypeTable Component="PackageFamilyDemo" />
```

| Name | Type | Default | Description |
|------|------|---------|-------------|
| `Columns` | `int` | `2` | Number of grid columns on desktop. |
| `Count` | `int` | `4` | How many packages to list, in dependency order. |

That table comes from this component:

```razor
@code {
    /// <summary>Number of grid columns on desktop.</summary>
    [Parameter] public int Columns { get; set; } = 2;

    /// <summary>How many packages to list, in dependency order.</summary>
    [Parameter] public int Count { get; set; } = 4;
}
```

## Where each column comes from

| Name | Type | Default | Description |
|------|------|---------|-------------|
| `Prop` | `name` |  | Every public property marked with the Parameter attribute. EditorRequired adds the Required chip. |
| `Type` | `C# type` |  | Written compactly, with nullability and generic arguments. |
| `Default` | `value` |  | From a DefaultValue attribute if present, otherwise read from a new instance of the component. Empty strings and render fragments show as a dash. |
| `Description` | `text` |  | The property's XML doc summary. |

## Turning on descriptions

Descriptions are read from the XML documentation file next to the assembly. Enable it in the project that owns the components:

```xml
<PropertyGroup>
  <GenerateDocumentationFile>true</GenerateDocumentationFile>
  <NoWarn>$(NoWarn);CS1591</NoWarn>
</PropertyGroup>
```

`CS1591` is the "missing XML comment" warning. Suppress it unless you want a warning for every undocumented member.

Without an XML file the table still renders, with a dash in the description column. A component library from NuGet shows descriptions when its package ships the `.xml` file.

## Generic components

A generic component lists its type parameters first, marked required, then its props. Defaults are read from an instance closed over `object` when the constraints allow it.

## Unknown component

If `Component` doesn't match a registered type, the table shows a single row saying so.

## AutoTypeTable or TypeTable

| Name | Type | Default | Description |
|------|------|---------|-------------|
| `AutoTypeTable` | `generated` |  | Component props. Always matches the code. |
| `TypeTable` | `hand-written` |  | Anything that isn't a component: CLI flags, options, tokens. Also when you want wording that differs from the doc comments. |

## Props

| Name | Type | Default | Description |
|------|------|---------|-------------|
| `Component` (required) | `string` | `—` | Tag name of a registered component. |

## See also

- [TypeTable](https://shelldocs.shellui.dev/docs/components/type-table.md): The hand-written table.
- [DemoPreview](https://shelldocs.shellui.dev/docs/components/demo-preview.md): Show the component next to its table.